Channel inductor

Abstract

A channel inductor of a channel induction furnace, the channel inductor comprising (a) a channel liner and (b) a back-up liner that supports the channel liner such that the integrity of the channel liner is not compromised during heat-up, dry-out, or operation of the channel induction furnace.

The invention claimed is: 
     
       1. A channel inductor of a channel induction furnace for an Al/Zn alloy that contains sodium, the channel inductor comprising: (a) a channel liner in contact with molten alloy in the furnace, wherein the material of the channel liner includes a source of silicon in the original material of the channel liner, and the channel liner includes a denser phase formed as a result of a chemical reaction between the original material of the channel liner and the molten alloy, with the denser phase making the channel liner more resistant to penetration by molten alloy and more resistant to the development of channel blockages, and (b) a back-up liner that supports the channel liner such that the integrity of the channel liner is not compromised during heat-up, dry-out, or operation of the channel induction furnace, wherein the material of the back-up lining is an aluminosilicate refractory composite material that contains 60-95 wt. % alumina that is capable of absorbing stresses due to expansion and movement of the channel liner. 
     
     
       2. The channel inductor defined in  claim 1  wherein the material of the back-up liner is also capable of resisting cracking due to thermal stress. 
     
     
       3. The channel inductor defined in  claim 1  wherein the material of the back-up liner is a dry vibratory material. 
     
     
       4. The channel inductor defined in  claim 1  wherein the aluminosilicate refractory composite material of the back-up liner has metal fibre reinforcing. 
     
     
       5. The channel inductor defined in  claim 1  wherein the refractory material component of the composite contains 60-70 wt. % alumina and 20-35 wt. % silica. 
     
     
       6. The channel inductor defined in  claim 1  wherein the channel liner is an elongate unit with the channel being in the shape of a single U. 
     
     
       7. The channel inductor defined in  claim 1  wherein the channel liner is an elongate unit with the channel being in the shape of a double U. 
     
     
       8. The channel inductor defined in  claim 1  wherein the material of the channel liner includes silicon carbide when the molten material is an Al/Zn-containing alloy that contains sodium. 
     
     
       9. The channel inductor defined in  claim 1  wherein the material of the back-up lining is an aluminosilicate refractory composite material which has steel fibre reinforcing. 
     
     
       10. A channel inductor furnace that comprises:
 (a) a steel shell, 
 (b) a lining of a refractory material internally of the shell, 
 (c) a pot for containing a pool of molten metal that is defined by the refractory-lined shell, and 
 (d) at least one of the channel inductor for heating a metal that is defined in  claim 1  and connected to the shell and in fluid communication with the pot via a throat that extends through the shell and the refractory lining to the inlet in the channel inductor.